The present invention relates to improved gypsum moldings having an improved mechanical strength and fire-resisting property, and to a process for preparing thereof.
Gypsum can be obtained cheaply almost all over the world and moldings thereof have a comparatively high strength at a normal temperature, so gypsum moldings have been used for building materials, e.g. a panel and a block for wall and ceiling.
However, gypsum moldings have a high bulk density and poor fire-resisting property, that is, when heated at high temperature, their mechanical strength such as bending strength or compressive strength decreases exceedingly and shrinkage, deformation or crack often occurs.
Therefore, such gypsum moldings are not applicable to the use of modern building materials which require light bulk density and superior heat insulating property.
There has been proposed a process for improving a mechanical strength of moldings made of gypsum by admixing a reinforcing material, for instance, cellulose fiber, mineral fiber such as asbestos or rock wool, or perlite into gypsum, but such a process is insufficient to improve fire-resisting property of moldings.